This paper, by means of the fractal method and fractal dimension D, studies preliminarily on the temporal fractal structure of seismic activity in the Menyuan area during 1970-1985. The result shows that there is D value and it changes from 0.58 to 0.42 before the Menyuan earthquake(M=6.4). It indicates that the temporal structure of seismic activity in this area trends forward more neterogeneows, i. e. the symmetry is broken or the ordering is strengthened, when the strong earthquake is more approaching to occur.
The ordering has the characteristic of the multiple levels with self similar mosaic structures. It has not only the prediction meaning but also the theoretical meaning.